Meteor observations with the European Incoherent Scatter UHF Radar

摘要: The European Incoherent Scatter (EISCAT) UHF radar, which operates at a nominal frequency of 930 MHz, is introduced as powerful meteor radar. Its high sensitivity utilized to detect transient enhanced ionization trails caused by meteors all orientations, in contrast conventional HF and VHF backscatter radars, observe only the oriented approximately normal radar beam. A comparison shows that EISCAT observes almost hourly rates radars do, spite its beamwidth being 0.5° compared their 100°. Two different kinds echoes are seen data. About three fourths them strongly Doppler-shifted echoes, we interpret head since they move with velocities. remaining long-lived. They come from ionized left behind meteors, drift slowly or not all. There fundamental differences between scattering process producing both types observed radars. For example, have never trail appear after echo. All our shower also nonspecular. We postulate some time required for expand within approach thermal equilibrium state order give detectable incoherent echoes. Due very small cannot follow motion an individual meteor, can, but can obtain statistical profile what happens heights meteoroids penetrate atmosphere. altitude distribution observable over whole measurement range about 65 165 km, while be detected narrow range. latter effect probably related radio ceiling effect.